The field of the invention relates to cardiac monitoring and more particularly to methods of distinguishing between different types of cardiac abnormalities.
Atrial fibrillation (AFIB) and atrial flutter (AFL) are two of the most common abnormal cardiac rhythms, constituting up to 8% of electrocardiograms (ECGs) collected by hospitals. The two rhythms have clinically different implications and require different management. In addition, fibrillatory and flutter waves have different generating mechanisms in the atria. However, these two rhythms are often cross classified by physicians and by computerized ECG analysis systems for two main reasons. First, patterns of atrial flutter and fibrillation often coexist within the same ECG segment examined. The second cause of cross-classification is due to the difficulty of detecting atrial activity (visually or by computer time-based analysis) due to the overlying (and dominant) waveforms of ventricular origin (i.e., the QRS complex and T-wave), especially in the case of high ventricular rates.
A method and apparatus are provided for differentiating among atrial-flutter, atrial-fibrillation and other cardiac rhythms. The method includes the steps of estimating a spectral entropy of atrial cardiac activity from an electrocardiogram of a patient and determining that the patient has atrial fibrillation when the spectral entropy is greater than a predetermined value.